<s>
The	O
6bone	B-Protocol
was	O
a	O
testbed	O
for	O
Internet	B-Protocol
Protocol	I-Protocol
version	I-Protocol
6	I-Protocol
;	O
it	O
was	O
an	O
outgrowth	O
of	O
the	O
IETF	O
IPng	B-Protocol
project	O
that	O
created	O
the	O
IPv6	B-Protocol
protocols	O
intended	O
to	O
eventually	O
replace	O
the	O
current	O
Internet	O
network	O
layer	O
protocols	O
known	O
as	O
IPv4	B-Protocol
.	O
</s>
<s>
The	O
6bone	B-Protocol
was	O
started	O
outside	O
the	O
official	O
IETF	O
process	O
at	O
the	O
March	O
1996	O
IETF	O
meetings	O
,	O
and	O
became	O
a	O
worldwide	O
informal	O
collaborative	O
project	O
,	O
with	O
eventual	O
oversight	O
from	O
the	O
"	O
NGtrans	O
"	O
(	O
IPv6	B-Protocol
Transition	O
)	O
Working	O
Group	O
of	O
the	O
IETF	O
.	O
</s>
<s>
The	O
original	O
mission	O
of	O
the	O
6bone	B-Protocol
was	O
to	O
establish	O
a	O
network	O
to	O
foster	O
the	O
development	O
,	O
testing	O
,	O
and	O
deployment	O
of	O
IPv6	B-Protocol
using	O
a	O
model	O
to	O
be	O
based	O
upon	O
the	O
experiences	O
from	O
the	O
Mbone	B-Protocol
,	O
hence	O
the	O
name	O
"	O
6bone	B-Protocol
"	O
.	O
</s>
<s>
The	O
6bone	B-Protocol
started	O
as	O
a	O
virtual	B-Protocol
network	I-Protocol
(	O
using	O
IPv6	B-Protocol
over	O
IPv4	B-Protocol
tunneling/encapsulation	O
)	O
operating	O
over	O
the	O
IPv4-based	O
Internet	O
to	O
support	O
IPv6	B-Protocol
transport	O
,	O
and	O
slowly	O
added	O
native	O
links	O
specifically	O
for	O
IPv6	B-Protocol
transport	O
.	O
</s>
<s>
Although	O
the	O
initial	O
6bone	B-Protocol
focus	O
was	O
on	O
testing	O
of	O
standards	O
and	O
implementations	O
,	O
the	O
eventual	O
focus	O
became	O
more	O
on	O
testing	O
of	O
transition	O
and	O
operational	O
procedures	O
,	O
as	O
well	O
as	O
actual	O
IPv6	B-Protocol
network	O
usage	O
.	O
</s>
<s>
The	O
6bone	B-Protocol
operated	O
under	O
the	O
IPv6	B-Protocol
Testing	O
Address	O
Allocation	O
(	O
see	O
)	O
,	O
which	O
specified	O
the	O
3FFE::/16	O
IPv6	B-Protocol
prefix	O
for	O
6bone	B-Protocol
testing	O
purposes	O
.	O
</s>
<s>
At	O
its	O
peak	O
in	O
mid-2003	O
,	O
over	O
150	O
6bone	B-Protocol
top	O
level	O
3FFE::/16	O
network	O
prefixes	O
were	O
routed	O
,	O
interconnecting	O
over	O
1000	O
sites	O
in	O
more	O
than	O
50	O
countries	O
.	O
</s>
<s>
When	O
it	O
became	O
obvious	O
that	O
the	O
availability	O
of	O
IPv6	B-Protocol
top	O
level	O
production	O
prefixes	O
was	O
assured	O
,	O
and	O
that	O
commercial	O
and	O
private	O
IPv6	B-Protocol
networks	O
were	O
being	O
operated	O
outside	O
the	O
6bone	B-Protocol
using	O
these	O
prefixes	O
,	O
a	O
plan	O
was	O
developed	O
to	O
phase	O
out	O
the	O
6bone	B-Protocol
(	O
see	O
)	O
.	O
</s>
<s>
The	O
phaseout	O
plan	O
called	O
for	O
a	O
halt	O
to	O
new	O
6bone	B-Protocol
prefix	O
allocations	O
on	O
1	O
January	O
2004	O
and	O
the	O
complete	O
cessation	O
of	O
6bone	B-Protocol
operation	O
and	O
routing	O
over	O
the	O
6bone	B-Protocol
testing	O
prefixes	O
on	O
6	O
June	O
2006	O
.	O
</s>
<s>
Addresses	O
within	O
the	O
6bone	B-Protocol
testing	O
prefix	O
have	O
now	O
reverted	O
to	O
the	O
IANA	O
.	O
</s>
